Blood supply safer with newer, pricier tests

Posted: Wednesday, July 19, 2000

By Erin McClamAssociated Press

ATLANTA -- New genetic tests have made the nation's blood supply safer, allowing donation banks to detect viral infections sooner and keep them from slipping into transfusions, scientists said Tuesday.

Dr. Michael Busch of Blood Centers of the Pacific said nucleic acid testing, which can detect tiny amounts of viruses like HIV and hepatitis C even before the body recognizes them, has stopped a ''significant'' number of infections.

Traditional testing has depended on antibodies that the immune system develops to fight the virus, but those reactions can take up to 80 days.

Nucleic acid testing, or NAT, has cut that window down to less than 20, Busch reported Tuesday at the International Conference on Emerging Infectious Diseases.

Busch said the American Red Cross used NAT to screen 7.7 million blood donations from March 1999, when the procedure was introduced, through last month. He said the testing found one HIV infection and 25 hepatitis C infections -- each of which could have been passed to up to three patients by transfusion.

Other blood banks have screened about 9 million donations, finding three HIV infections and more than 35 hepatitis C infections, he said.

The Food and Drug Administration is strongly encouraging blood banks to use genetic testing and hospitals to exclusively use NAT-screened blood.

Scientists hope NAT will eliminate the few cases of HIV annually caused by donated blood and prevent most annual cases of hepatitis C transmission through blood.

The genetic tests also promise that if a brand new virus ever sneaks into the blood supply as AIDS did two decades ago, blood banks could protect Americans much faster.

Still, scientists are concerned about the high cost of NAT compared to traditional antibody screening, Busch said. While traditional methods actually save the public money by preventing viral transmission, NAT's cost-effectiveness is ''extraordinarily poor,'' he said.

''We're putting enormous resources into cleaning out these last few transmissions,'' he said.

Busch said the high cost should draw attention to the grave state of public health in developing countries, some of which do not screen up to 40 percent of donated blood at all.